I always use Scalibor collars for my dogs against ticks, fleas and mosquitos and Bayer collars for my cats.
During some summers, it seems that fleas developped some kind of immunity to those products and they weren't enough, as a result my house was full of fleas, they bite mostly the legs of humans cause they do not fly, only walk on the floor and jump. Do not mix them with mosquitos' bites cause you might imagine never ending fleas problem after having extinguished them!
I used Bolfo spray for all rooms floors, the animals beds and my bed matresses, bedspreads and so on.
I used except from above products, Frontline spray for cats and Advantix capsules for all dogs, for some of them more than once, (one may use Advantix capsules each 15 days in extreme circumstances), but it is substantial all products used for dogs to be applied in all of them in same time, and all products used for cats to be applied in all the cats simultaneously.
Careful cause Advantix if licked by cats can be lethal, always keep cats away from dogs until Advantix on their hair is completely dry.
(My cats sleep together with my dogs, that's why I say it).
If all above is not enough one can always shampoo dogs with some special product for fleas, although I never shampoo cats.
When thinking having extinguished fleas as I said before, maybe psychologically one needs support, so I used to place on each floor's room a bowl with soap water under a lamp (table lamp, reading lamp) if fleas still exist, one or two will drop inside, if they do not drop, they do not exist any more, end of alarm.
During above process it's understood I was washing all clothes of the house (curtains, sheets and blankets and my own clothes) in the washing machine again and again.
When one has fleas on the house he'll know it, when not I believe it's enough a collar and some capsule, but one must be careful of new-comers.
A new animal is better to be sprayed with Frontline even before to come close to the house.
Good luck!